Non-Repudiation
Property of an authorization system where decisions cannot be denied after the fact. Cryptographic receipts provide verifiable proof that a specific decision was made at a specific time.
Non-repudiation is the property of an authorization system where decisions cannot be denied after the fact. A user cannot claim "I was told to approve that" and the system cannot claim "that decision was never made." It is achieved through cryptographic receipts — signed, verifiable proof tokens that link every decision to a specific identity, time, and policy.
Why non-repudiation matters
In a standard authorization system, the audit log is a database that the operator controls. A malicious operator could delete entries, modify timestamps, or fabricate decisions. Non-repudiation solves this: each receipt is independently verifiable, so an auditor can validate the audit trail without trusting the operator.
Verification without trust
Cryptographic receipts can be verified offline using the published verification key. An auditor receives the receipts, checks the signatures against the key, validates the Merkle chain, and confirms the audit trail's integrity — all without accessing the live authorization service.
Related terms
Security control that prevents a single user from performing conflicting operations. For example, the same person cannot both create and approve a payment — requires two distinct identities.
Immutable, chronological record of every authorization decision — who, what, when, scope, resource, action, and outcome. Enables compliance reporting and incident investigation.
Signed, verifiable proof tokens produced for every authorization decision. Non-repudiable audit trail that can be verified without trusting the authorization service.